1. Field of the Invention
The present invention relates to a technology for estimating a demand for a service offered on a network.
2. Description of the Related Art
Conventionally, various services (such as, portal sites, shopping sites, or weather forecasting sites of a certain company) have been offered to users on the network. Demands for such services seasonally change. However, in order to avoid losses such as one caused by insufficient resources (for example, the number of Web servers and application (AP) servers, and the storage size) during a season and one caused by excessive resources out of a season, it is important to allocate an appropriate amount of resources to the services according to the demands for the services (the number of access by users) in view of operation of the services.
When the content of resources is changed according to the demands for the service, the resource changing operation takes a few minutes to several tens of minutes. Therefore, in view of operation of services, it is essential to start the resource changing operation before the demands vary, by estimating the demands, in order to allocate adequate resources at the right time corresponding to the demands. Accordingly, for example, a technique for estimating demands based on past results of demands has been developed (see, for example, Japanese Patent Application Laid-open No. 2001-67377).
However, there is a problem in that the conventional technique cannot follow the current demands, which changes fast in a complicated manner. That is, in the current network society, the demands of users are affected by information released on the Internet (for example, when a product of a certain company appears on a news site, the number of accesses to the company's website increases immediately). Therefore, the conventional technique for estimating the demands based on the past results of demands cannot handle the fluctuations in the demands specific to the network. As a result, the conventional technique cannot follow today's demands that change fast in a complicated manner.